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  1. #1
    TBerk's Avatar
    TBerk Guest

    Default Viewing from the Bottom of a Very Large Cylinder




    I was thinking, esp in terms of those of us affected by washout and
    glare from being in or near Metro area with all the attendant Light
    Pollution.

    I imagine a very large cylinder, say a ten meter diameter. Hight might
    be min 3x-5x the diameter, and (possibly) would be more useful if it
    could be manoeuvred (pointed) and collapsed when not in use.

    Basic premise is that there might be some benefit from blocking out
    stray light from the sides, perhaps other benefits as well.

    I seem to recall something about star gazing from the bottom of a
    well... but it's a slippery recollection.

    Anyone experienced anything like this?


    berk
    currently under influence of Bar-B-Q'd Turkey and Chocolate Cream
    Pie...
    currently under influence of Bar-B-Q'd Turkey and Chocolate Cream
    Pie...

  2. #2
    wsnell01@hotmail.com's Avatar
    wsnell01@hotmail.com Guest

    Default Viewing from the Bottom of a Very Large Cylinder

    On Dec 19, 2:23 am, TBerk <bayareab...@yahoo.com> wrote:

    It might help to block out ambient light, but won't make the sky any
    darker.


    http://www.snopes.com/science/well.asp


  3. #3
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default Viewing from the Bottom of a Very Large Cylinder

    On Fri, 18 Dec 2009 23:23:33 -0800 (PST), TBerk <bayareaberk@yahoo.com>
    wrote:


    There would be no benefits except blocking stray light- the same reason
    people use shields and tents for viewing in areas with high ambient
    light. Your cylinder would need to extend upwards for thousands of
    meters to be above the worst of scattered light. (Obviously, you could
    construct special cases where a short cylinder would be helpful, like if
    your neighbor had a spotlight that was lighting up misty or dusty air
    just above your scope.)


    Aristotle proposed that you could see stars from the bottom of a well,
    and the story has been repeated over the centuries. This is false; the
    sky (what you can see of it) looks exactly the same from the bottom of a
    well as it does from the top. A cylinder extending upwards from the
    surface is a little different, of course, because it can actually block
    surface light interference. But to block enough to matter, it would have
    to be impractically long.
    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

 

 

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